A new University of
Southern California study, which appears in the April
edition of Civil Engineering magazine, finds that the
potential damage from a tsunami in Southern California
could range from $7 billion to as much as $42 billion.

The report is the first
attempt to calculate possible losses from tsunamis, as
opposed to earthquakes, in the Southern California area.

Entitled 'Could it happen
here'' the article builds on research by Jose Borrero,
assistant research professor of civil engineering, and
Costas Synolakis, professor of civil engineering, at the
USC Viterbi School of Engineering regarding tsunamis
caused by underwater landslides in unstable sediments
off Palos Verdes peninsula. Synolakis is director of the
USC Viterbi School Center for Tsunami Research.

A tsunami in this area
could inundate Terminal Island and much of the ports of
Los Angeles and Long Beach, as well as producing
substantial run-up on Orange County beach cities, with
maximum waves arriving only one minute after the slide.
Municipalities potentially affected include Carson, Long
Beach, Wilmington/San Pedro, Palos Verdes Estates and
Rancho Palos Verdes, Seal Beach, Westminster, Garden
Grove, Huntington Beach, Hawaiian Gardens, and
unincorporated areas of Los Angeles and Orange Counties.

The study uses methodology
co-created by one of the authors, Harry W. Richardson,
who holds the James Irvine Chair in Urban and Regional
Planning at the USC School of Policy, Planning and
Development, with a PPD colleague, Professor Peter
Gordon. This scheme breaks down Southern California into
308 zones, whose individual contribution to the area's
economy is noted in detail, along with their economic
connections to other zones.

Researchers used an
improved version of the system, called the Southern
California Planning Model, to incorporate effects caused
by damage to the highway system.

James Moore II, who is a
professor of Industrial and Systems Engineering, Civil
Engineering and Public Policy and Management at the
Viterbi School, worked with Richardson on the
application of the model to a tsunami. "We have not
attempted to account for the cost of fatalities in our
estimates," said Moore. "We chose not to model
fatalities because we were being deliberately
conservative, and because we wanted to avoid contentious
assumptions about the economic value of life." Moore
noted that "the Papua New Guinea tsunami of 1998 was
generated by a mechanism similar to the one modelled
here, and that event cost over 2,000 lives. The toll
here could be much higher."

The study assumed four
possible scenarios, of increasing severity. In scenario
one, losses were confined to inundated areas, with no
freeway links closed, and no crippling damage to the
ports of Los Angeles/Long Beach. The following three
scenarios assumed escalating problems, with a worst case
being closure of critical freeway links and the ports
for one year, forcing the shipment of $83 billion in
exports now going through these facilities elsewhere.

The study also breaks down
direct losses by municipality, with Long Beach suffering
some $3.6 billion in damage, by far the largest for any
single city.

The authors note that
these losses, significant as they are, would be only a
part of a general picture of damage. The most likely
trigger of a landslide off Palos Verdes would be a large
earthquake - which itself would produce billions in
damage.

"However, it is
important to remember that these tsunami costs would be
incurred in addition to earthquake costs," the authors
note.

In addition to Borrero,
Moore, Richardson and Synolakis, Sungbin Cho contributed
to the article from Continuity Central